Selective Catalyst Reduction (SCR) catalysts and liquid reductant (e.g., hydrocarbon or urea solution) injected into engine exhaust ducts may be used for reducing engine-out NOx emissions. However, heat from the engine exhaust may cause reductant injectors to overheat and may cause solids to deposit on the injector tip. The solid deposits may in turn result in clogging of the injector orifice.
One approach used to address injector overheating may be to use a small V-band clamp for connecting the injector and its mounting structure to the exhaust passage. The V-band serves to potentially insulate the injector from engine exhaust heat, thereby reducing solid deposit buildup.
However, the inventors herein have recognized that connecting the injector to the mounting structure using a V-band clamp may require special tools and may be too cumbersome to allow fast and easy assembly in a mass production environment. Likewise, premature degradation of the V-band clamp, due to assembly installation variation, for example, may increase exhaust leakage.
A system for injecting from an injector into a duct of an engine system is provided herein to at least partially address above mentioned issues. The system may include a first flange on a duct connection side, a second flange on an injector connection side, a stand-off separating the first flange from the second flange to form an air gap therebetween, and a seal offset from at least one of the first and the second flanges and located within the air gap and between the first flange and the second flange.
In this way, it is possible to obtain a reliable, robust, and time-efficient connection of the injector with reduced contact surface area between potentially high temperature injector components and the injector via the seal positioned in the air gap formed by the stand-off.